The only true limit to how scale you can go is your access to funding. They are some truley beautiful scale jobs out there, with working everything. Just get the wallet out & keep shoveling money at it.

Some of my favorite very scale kits are done by Proctor (WWI). Nick Ziroli puts out some plans that you can enhance to scale.

It helps to have a machine shop in your garage though. Mill, Lathe & drill press minimum.

Have fun!!